First Author:   Richard Duhautois CEE-TEPP, University of Paris-Est- Marne-la-Vallée and CREST richard.duhautois@enpc.fr         Second Author: Emmanuelle Walkowiak University of Paris 12-ERUDITE and CEE emmanuelle.walkowiak@univ-paris12.fr         Third Author: Oana Calavrezo LEO, University of Orleans and CEE oana.calavrezo@etu.univ-orleans.fr